Plasma processing apparatus and plasma processing method using the same

ABSTRACT

A plasma processing apparatus is provided with at least one waveguide portion for introducing microwaves, an electron heating space chamber formed on a downstream side with respect to a dielectric body in the waveguide portion, and a plasma generating space chamber coupled with the electron heating space chamber. A first static magnetic field generating device surrounds the electron heating space chamber using permanent magnets, producing a strong magnetic field exceeding an electron cyclotron resonance magnetic field strength along a propagation direction of the microwave in the electron heating space chamber and in a microwave leading-out portion of the dielectric body, and forming a cusped magnetic field. This cusped magnetic field falls steeply from a position of electron cyclotron resonance magnetic field strength to a boundary portion between the electron heating space chamber and the plasma generating space chamber and its direction is reversed to that of the strong magnetic field with decreasing distance from the boundary portion between the electron heating space chamber and the plasma generating space chamber to the plasma generating space chamber. A second static magnetic field generating device is provided with permanent magnets arranged around the plasma generating space chamber. Adjacent ones of the permanent magnets have polarities opposite to each other.

BACKGROUND OF THE INVENTION

The present invention relates to a plasma processing apparatus and to aplasma processing method using the same suitable for uniform plasmaprocessing over a large area, which works specifically under a low gaspressure in a processing step using plasma such as plasma etching, iondoping, plasma CVD film formation, sputtering film formation, etc. forfabricating semiconductor devices, etc.

As prior art techniques for this kind of plasma processing apparatusesthere are known those reported e.g. in J. Vac. Sci. Technol. B9(1),January/February 1991, p.26˜p.28. In this paper it is described that amagnetic field similar to that formed by a solenoid coil used as meansfor generating a first static magnetic field described ibid. p.29˜p.33can be realized by means of permanent magnets. In this example permanentmagnets for replacing the solenoid coil magnetic field should be huge.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a microwave plasmaprocessing apparatus capable of effecting plasma processing in a uniformhigh density plasma having a large extent by decreasing the size of thepermanent magnets.

Another object of the present invention is to provide a microwave plasmaprocessing apparatus capable of effecting plasma processing in a uniformplasma having a large extent, on which influences of the magnetic fieldare suppressed.

Still another object of the present invention is to provide a microwaveplasma processing apparatus capable of generating a uniform high densityplasma having a large extent for plasma processing.

The prior art techniques have problems described below, because thepermanent magnets, which are the means for generating the first staticmagnetic field, are huge.

That is, at first, they have a problem that fabrication cost of thepermanent magnets is correspondingly high. Attenuation rate of magneticfield at places distant from the permanent magnets is small andtherefore strong magnetic field remains on a matter which is to beprocessed. For this reason, there is a problem that these techniques areunsuitable for processing matters sensitive to magnetic field, e.g.magnetic films, etc. Further, since in the magnetic field generated byhuge permanent magnets attenuation in strength is small and thus spatialmagnetic field gradient is small, spatial variations in propagation andabsorption of microwaves are great, which gives rise to instability ofdischarge.

In general, from a point of view of quality of plasma, in order to makeplasma uniform in a large extent, plasma generated in a strong magneticfield produced by the first static magnetic field generating means isdiffused into a weak magnetic field region enclosed by a superficialmagnetic field produced by a second static magnetic field generatingmeans. Therefore a major part of generated ions traverse the magneticfield and kinetic energy of ions accelerated by gradient in plasmapotential is transformed into thermal energy, which increases iontemperature. Further, separation of different kinds of ions takes placedue to the difference in cyclotron radius in the magnetic field and inaddition radicals generated at the same time as the plasma are also notmade uniform by action of the electromagnetic field, which gives rise tostill another problem that plasma processing is made non-uniform.

By the present invention a microwave plasma processing apparatus isprovided, which can generate a uniform high density plasma having alarge extent at a low cost by decreasing the size of the permanentmagnets, in view of the problems of the prior art techniques, and whichcan subject matters to be processed to uniform plasma processing over alarge area by using plasma thus generated, suppressing influences ofmagnetic field thereon.

The present invention is characterized in that it comprises at least onewaveguide portion for introducing microwave; an electron heating spacechamber portion formed on a downstream side with respect to a dielectricbody in the waveguide portion; a plasma generating space chamber portioncoupled to the electron heating space chamber portion; first staticmagnetic field generating means surrounding the electron heating spacechamber portion by means of permanent magnets, which produce a strongmagnetic field exceeding an electron cyclotron resonance magnetic fieldstrength along a transmission direction of the microwave in the electronheating space chamber portion and in a microwave leading-out portion ofthe dielectric body, and which form a cusped magnetic field, which fallssteeply from a position of electron cyclotron resonance magnetic fieldstrength to a boundary portion between the electron heating spacechamber portion and the plasma generating space chamber portion and adirection of which is reversed to that of the strong magnetic field withdecreasing distance from the boundary portion between the electronheating space chamber portion and the plasma generating space chamberportion to the plasma generating space chamber portion; second staticmagnetic field generating means consisting of permanent magnets arrangedaround the plasma generating space chamber portion, every two of whichhave polarities opposite to each other; and means for holding a matterto be processed opposite to the plasma generating space chamber portion.

It is characterized further in that it comprises a counterplate disposedin front of the plasma generating space chamber portion, opposite to thematter to be processed; and means for applying a bias voltage to thecounterplate.

According to the present invention, when the waveguide portion is fedwith microwave, since the electron heating space chamber portion isformed on the downstream side with respect to the dielectric body in thewaveguide portion and that space chamber portion is disposed within thewaveguide portion having a small width in the direction of microwaveelectric field, it is possible to introduce microwaves having a strongelectric field into the electron heating space chamber portion. Further,since microwaves are introduced into the electron heating space chamberportion from the strong magnetic field side having a strength exceedingan electron cyclotron resonance magnetic field strength, even if aplasma having a density higher than a cut-off density as plasma isproduced, it is possible to have microwaves reach an electron cyclotronresonance layer with a high efficiency. Still further, since the widthof the electron heating space chamber portion is so small as describedabove, the size of the permanent magnets acting as the first staticmagnetic field generating means arranged around it can be reduced.

In addition, since the permanent magnets acting as the first staticmagnetic field generating means form a magnetic field having a greatgradient in the neighborhood of the electron cyclotron resonancemagnetic field strength in the electron heating space chamber portion,even if a magnetic field strength at which microwaves are easilyabsorbed varies, depending on the state of plasma, it is possible tosuppress spatial variations of microwave absorption positions to a valuesufficiently small with respect to microwave wavelength. Consequently itis possible to eliminate instability factors concerning propagation andabsorption of microwaves as far as possible and therefore to feed surelyand stably the electron heating space chamber portion with microwaveshaving a high electric field. In this way, in the electron heating spacechamber portion, it is possible to have electrons absorb almost allmicrowaves to heat them and to obtain high energy electrons.

At this time, since the permanent magnets acting as the first staticmagnetic field generating means form a cusped magnetic field, themagnetic field direction of which is reversed on the further downstreamside from the boundary portion between the electron heating spacechamber portion and the plasma generating space chamber portion asdescribed above, electrons close to the axis of the electron heatingspace chamber portion are easily diffused towards the plasma generatingspace chamber portion. In addition, since the magnetic field produced bysmall permanent magnets is attenuated steeply with increasing distance,a large region within the plasma generating space chamber portion can besuch a weak magnetic field region that high energy electrons in chargeof ionization wander about, traversing the magnetic field. The weakmagnetic field region in this meaning is a region where the magneticfield strength is usually lower than about 30 G.

The high energy electrons diffused in the plasma generating spacechamber portion collide with neutral particles while wandering in theweak magnetic field region within the plasma generating space chamberportion so that they can generate a plasma uniform over a wide region byionizing neutral particles. In addition, since a plurality of permanentmagnets acting as the second static magnetic field generating means arearranged around the plasma generating space chamber portion so thatevery adjacent two of them have polarities opposite to each other toform a multi-pole cusped magnetic field, it is possible to confine notonly diffused high energy electrons but also plasma produced by the highenergy electrons with a high efficiency and therefore to form a highdensity plasma in the plasma generating space chamber portion. Theplasma generated in the weak magnetic field region is hardly influencedby magnetic field and thus it has good properties that distribution ofdifferent kinds of ions is uniform and that ion temperature is low.Distribution of radicals produced in the weak magnetic field regiontogether with the plasma is also uniform.

By holding a matter to be processed opposite to the plasma generated asdescribed above, it is possible to effect plasma processing such asplasma etching, plasma CVD film formation, ion doping, etc. over a largearea.

Further, when the plasma processing apparatus has a counterplatedisposed in front of the plasma generating space chamber portion,opposite to the matter to be processed, and means for applying a biasvoltage to the counterplate, it is possible to reduce remarkablycontamination of the matter to be processed by particles by effectingplasma cleaning of the counterplate by applying a bias voltage to thecounterplate after a plasma CVD film formation processing, etc. Further,when a target is held on the surface of the counterplate, which isbrought into contact with the plasma, and sputter is effected whileapplying a bias voltage thereto, since the whole surface of the targetis sputtered, a high utilization efficiency of the target can beobtained. In addition, if an operation is effected under a low gaspressure, sputtered particles fly well straight and therefore sputterfilm formation having a good step coverage with respect to the matter tobe processed is made possible.

As described above, since a plasma processing apparatus is soconstructed that an electron heating space chamber portion is disposedso that microwaves having a strong electric field can be introducedstably into a waveguide, that permanent magnets acting as first staticmagnetic field generating means arranged on the outer periphery of theelectron heating space chamber portion generate a strong magnetic fieldexceeding an electron cyclotron resonance magnetic field strength in amicrowave leading-out portion of a dielectric body, that at the sametime the magnetic field falls steeply from an electron cyclotronresonance magnetic field strength to a boundary portion between theelectron heating space chamber portion and a plasma generating spacechamber portion, and that a cusped magnetic field, whose direction isreversed to that of the strong magnetic field with decreasing distancefrom the boundary portion between the electron heating space chamberportion and the plasma generating space chamber portion to the plasmagenerating space chamber portion, is formed, the size of the permanentmagnets can be reduced and they become cheaper correspondingly. Inaddition, since a plurality of permanent magnets acting as second staticmagnetic field generating means are arranged around the plasmagenerating space chamber portion, every adjacent two of which havepolarities opposite to each other, a high density plasma, which isuniform over a wide region, can be surely formed in the whole plasmagenerating space chamber portion. Further, owing to the fact that thereis almost no magnetic field on a matter to be processed and that it canbe surely utilized for the purpose of work of magnetic films, etc., ithas an effect that processed matters of good quality having a large areacan be stably obtained.

Further, owing to the fact that there are disposed a counterplate infront of the plasma generating space chamber portion, opposite to thematter to be processed, and means for applying a bias voltage to thecounterplate, it is possible to effect plasma cleaning of thecounterplate while applying a bias voltage to the counterplate afterplasma CVD film formation, etc. and therefore to reduce contamination ofthe matter to be processed by particles. Further, when a target is heldon the surface of the counterplate, which is brought into contact withthe plasma, and sputter is effected while applying a bias voltagethereto, since the whole surface of the target is sputtered, a highutilization efficiency of the target can be obtained. In addition, if anoperation is effected under a low gas pressure, sputtered particles flywell straight and therefore sputtering film formation having a good stepcoverage with respect to the matter to be processed is made possible.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view for explaining a first embodiment ofthe plasma processing apparatus according to the present invention;

FIG. 2 is a front view of the plasma processing apparatus shown in FIG.1;

FIG. 3 is a plan view of the plasma processing apparatus shown in FIG.1;

FIG. 4A is an enlarged diagram showing a principal part of the presentinvention;

FIG. 4B is a diagram showing a relation between high energy electroncurrent density and a plasma generating space chamber portion;

FIG. 4C is a graph showing a magnetic field strength distribution atdifferent positions in an electron space chamber portion and the plasmagenerating space chamber portion;

FIG. 5 is a cross-sectional view for explaining a second embodiment ofthe plasma processing apparatus according to the present invention;

FIG. 6 is a front view of the plasma processing apparatus shown in FIG.5;

FIG. 7 is a plan view of the plasma processing apparatus shown in FIG.5;

FIG. 8 is a cross-sectional view for explaining a third embodiment ofthe plasma processing apparatus according to the present invention;

FIG. 9A is an enlarged diagram showing a principal part of the thirdembodiment;

FIG. 9B is a graph showing a magnetic field strength distribution atdifferent positions in the electron space chamber portion and the plasmagenerating space chamber portion;

FIG. 10A is a cross-sectional view for explaining a fourth embodiment atplasma processing of the plasma processing apparatus according to thepresent invention;

FIG. 10B is a cross-sectional view for explaining the same apparatus asFIG. 10A at cleaning; and

FIG. 11 is a plan view of the plasma processing apparatus shown in FIG.10A.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Several embodiments of the present invention will now be explained,referring to FIGS. 1 to 11, in which FIGS. 1 to 4A-4C correspond to afirst embodiment of the present invention.

In the present embodiment a discharge chamber 100 is formed, whichchamber includes four electron heating space chamber portions 1, each ofwhich is formed in each of four waveguide portions 5, and a plasmagenerating space chamber portion 2, to a peripheral wall of which thefour waveguide portions 5 are coupled.

A specified gas is introduced into the discharge chamber 100 through gasintroducing means 7 while evacuating the discharge chamber by means ofan evacuating system not indicated in the figures to put the interior ofthe discharge chamber 100 in an atmosphere of that gas and microwavesare is introduced through the waveguide portions 5 into the dischargechamber 100 to generate plasma by giving rise to microwave dischargetherein. In this way it is possible to effect plasma processing such asplasma etching, plasma CVD film formation, ion doping, etc. by theplasma thus generated and radicals produced, accompanying it, on asubstrate 20 supported on a supporting table 21, to which an AC biasvoltage is applied by a high frequency power supply 23 and a matchingbox 22. The gas pressure at this plasma processing is a low gas pressureof about 10 ⁻⁵ to 10⁻³ Torr. Each of the waveguide portions 5 in thepresent embodiment consists in a rectangular waveguide (transversalwidth is 27 mm and depth is 96 mm) having a small transversal width madeof a non-magnetic material such as stainless steel and aluminium, inwhich a dielectric body 6 is mounted at an intermediate position inorder to hold air-tightness of the discharge chamber 100. It is soconstructed that, when microwaves having a frequency of 2.45 GHz usedusually is introduced from the upstream side not indicated in thefigures, only microwaves of the fundamental mode (mode TE₁₀) aretransferred to the downstream side. The dielectric body 6 is madeusually of ceramics such as quartz, alumina, etc.

In the present embodiment, the electron heating space chamber portion 1has a small cross-sectional shape formed at a position on the downstreamside in the microwave transmission direction from the dielectric body 6in the waveguide portion 5, as indicated in FIGS. 1 and 4A, and it is soconstructed that, when microwaves are introduced into the waveguideportion 5, the microwave introduced into the electron heating spacechamber portion 1 produce a strong electric field, owing to the factthat the electron heating space chamber portion 1 has a smallcross-sectional shape formed in the waveguide portion 5. The waveguideportion 5 formed by the rectangular waveguide, as described previously,has a length of about 30 mm in the axial direction.

The plasma generating space chamber portion 2 has a circular upper wall8a and a peripheral wall 8b therefor made of a non-magnetic materialsuch as stainless steel, aluminium, etc. and it is formed so as to behollow so that it has a space (inner diameter is 500 mm and distancebetween the upper wall 8a and the substrate 20 is 170 mm) much greaterthan the electron heating space chamber portion 1. Permanent magnets 3acting as first static magnetic field generating means are arranged onthe outer periphery of the electron heating space chamber portion 1. Thepermanent magnets 3 are made of samarium, cobalt, etc. having a greatresidual flux density (about 11000 G) and arranged so as to surround theouter periphery of the waveguide portion 5, disposed on the outerperiphery of the waveguide portion 5 along the axial length directionfrom the dielectric body 6 side to the downstream end, as indicated inthe figures, so that a magnetic field is formed along the transmissiondirection of the microwave, as indicated in FIGS. 1 and 4A-4C. At thistime, the magnetic field has a strength (about 950 G in the presentembodiment) exceeding an electron cyclotron resonance magnetic fieldstrength (875 G) in a microwave leading-out portion 6a of the dielectricbody 6, as indicated in FIGS. 4A and 4C. It is so constructed that, inaddition, it is steeply attenuated therefrom towards the downstream sideso that it is 0 at a position 14, where the magnetic field strength is 0in the neighborhood of the boundary between the ending side of theelectron heating space chamber portion 1 and the plasma generating spacechamber portion 2 and further that a cusped magnetic field can beformed, the magnetic field direction of which is reversed on thedownstream side therefrom to the plasma generating space chamberposition 2.

Further it is preferable that the distance from an electron cyclotronresonance layer 12 to the position 14, where the magnetic field strengthfalls to 0 in the neighborhood of the boundary between the electronheating space chamber portion 1 and the plasma generating space chamberportion 2, is smaller than the wavelength of the microwave supplied tothe waveguide portion 5. Each of the permanent magnets 3 forming such amagnetic field is 6 mm thick and 50 mm long in the magnetizationdirection and the length of the periphery thereof is 300 mm in thepresent embodiment.

A plurality of permanent magnets 4 acting as second magnetic fieldgenerating means are arranged on the outer periphery of the plasmagenerating space chamber portion 2. This plurality of permanent magnets4 are made of same material as the permanent magnets 3 acting as thefirst magnetic field generating means and consist of a first permanentmagnet group 4a on the upper wall 8a of the plasma generating spacechamber portion 2, in which permanent magnets are disposedconcentrically with a predetermined interval, a second permanent magnetgroup 4b on the side wall 8b of the plasma generating space chamberportion 2, in which permanent magnets are disposed with a predeterminedinterval along the side wall 8b, and further a third permanent magnetgroup 4c on the back side of the substrate 20 in the discharge chamber100. Every adjacent two of these permanent magnets 4 have polaritiesopposite to each other. In this way a multi-pole cusped magnetic fieldis formed within the plasma generating space chamber portion 2 and atthe same time a weak magnetic field region is formed in a wide region inthe plasma generating space chamber portion 2. In the figure referencenumeral 9 indicates magnetic lines of force representing the multi-polecusped magnetic field formed by the plurality of permanent magnets.Speaking for reference, in the present embodiment, the magnetic fieldstrength is 400 to 2400 G on the upper wall 8a and the side wall 8b,about 20 G at the central portion of the plasma generating space chamberportion 2, and lower than 10 G at the position of the substrate 20.Surrounded by this multi-pole cusped magnetic field, a weak magneticfield region weaker than 30 G is formed as a single space in the plasmagenerating space chamber portion 2 and occupies more than a half of theplasma generating space chamber portion 2 in volume.

The plasma generating apparatus in the present embodiment is constructedas described above and now an operation thereof will be explained.

When the discharge chamber 100 consisting of the electron heating spacechamber portion 1 and the plasma generating space chamber portion 2 isin a gas atmosphere and when the waveguide portion 5 is fed withmicrowaves having a frequency of 2.45 GHz, the waveguide portion 5,which is a rectangular waveguide, transfers only the fundamental mode.The electric field direction in this microwave transfer mode is inaccordance with the transversal width direction of the rectangularwaveguide, as indicated in FIG. 4A.

At transmission of the microwave, owing to the fact that the electronheating space chamber portion 1 is formed on the downstream side fromthe dielectric body 6 in the waveguide portion 5, it is possible tointroduce stably microwaves having a strong electric field into theelectron heating space chamber portion 1. Further, in the presentembodiment, since a rectangular waveguide 27 mm wide and 96 mm deep wasused for the waveguide portion 5, it was possible to realize an averagevalue of the microwave electric field strength of about 80 V/cm in thecross-section of the waveguide for inputted electric power of 400 W ofthe microwave. In addition, since microwaves are introduced into theelectron heating space chamber portion 1 from the strong magnetic fieldside exceeding the electron cyclotron resonance magnetic field strength,even if a high density plasma having a density higher than the cut-offdensity as plasma is produced, it is possible to have microwave reachthe electron cyclotron resonance layer 12 with a high efficiency.

When the electron heating space chamber portion 1 has such a smallcross-section as described above, the permanent magnets 3 acting as thefirst static magnetic field generating means arranged around it can havea small size. The permanent magnets 3 generate a magnetic field having astrength exceeding that of the electron cyclotron resonance magneticfield at the leading-out portion 6a of the dielectric body 6 in theelectron heating space chamber portion 1 and the magnetic field isattenuated therefrom so that the strength thereof decreases to 0 at apoint in the neighborhood of the boundary between the electron heatingspace chamber portion 1 and the plasma generating space chamber portion2. That is, distribution of the strength of the magnetic field generatedby the permanent magnets 3 is steeply attenuated. For this reason,although the electron cyclotron resonance layer 12 is thin and electronheating capacity per microwave electric field strength is small, sincethe electric field strength itself is sufficiently high within theelectron heating space chamber portion 1, it is possible to haveelectrons absorb microwaves almost completely to heat them. As theresult, the electrons can be transformed into high energy electrons.

Electrons called "high energy electrons" here are those which arecapable of ionizing gas and have an energy higher than about 10 eV. Itis a matter of course that they are different from those having such anenergy that cannot ionize gas.

Since a curve representing the distribution of the magnetic fieldstrength generated by the permanent magnets 3 falls steeply in theelectron heating space chamber portion 1 between the electron cyclotronresonance layer 12 and the position 14 where the magnetic field strengthis 0 in the neighborhood of the boundary of the plasma generating spacechamber portion 2, as indicated in FIG. 4C, and the length of thesevariations is smaller than the wavelength of the microwaves (about 12 cmin the present embodiment), it is possible to eliminate instabilityfactors concerning propagation and absorption of the microwaves as faras possible and to utilize surely and stably microwaves having a highelectric field for electron heating.

In general, electrons move approximately along magnetic lines of forcein a strong magnetic field, but in a region where the magnetic field isweak they can easily traverse magnetic lines of force. For this reason,electrons in the electron heating space chamber portion 1 on the endingside thereof, i.e. electrons existing in the neighborhood of theposition 14 where the magnetic field strength is 0 in the neighborhoodof the boundary between the electron heating space chamber portion 1 andthe plasma generating space chamber portion 2, can wander about in ashaded region in the figure. In this case, since electrons are heated tohave a high energy, when they pass through an electron cyclotronresonance layer 12a or 12b, high energy electrons are diffused into theplasma generating space chamber portion 2 along the region of the cuspedmagnetic field and collide with neutral particles to ionize them,generating plasma, while wandering about in that region. Low energyelectrons generated at this time enter the electron heating spacechamber portion 1 while moving in the region of the multi-pole cupsedmagnetic field to be heated while passing through the electron cyclotronresonance layer 12a or 12b so that they become high energy electrons,which are in charge of ionization.

In this case, since the permanent magnets 3 form a cusped magneticfield, the magnetic field direction of which is reversed on the furtherdownstream side from the portion where the magnetic field strength is 0at the position 14 in the neighborhood of the boundary between theelectron heating space chamber portion 1 and the plasma generating spacechamber portion 2, as indicated in FIGS. 4A and 4C, current density ofhigh energy electrons flying from the electron heating space chamberportion 1 to the plasma generating space chamber portion 2 variesaccording to a curve indicated in FIG. 4B, which has a peak on thecenter axis of the electron heating space chamber portion 1. For thisreason, it is possible to promote plasma formation in a region distantfrom the electron heating space chamber portion 1, i.e in a weakmagnetic field region within the plasma generating space chamber portion2.

In general, under a low gas pressure (10⁻⁵ ˜10⁻³ Torr), since mean freepaths required for electrons to ionize neutral particles amount severalmeters to several tens of meters, high energy electrons wander about atrandom in the weak magnetic field region while being reflected a numberof times by the multi-pole cusped magnetic field surrounding the plasmagenerating space chamber portion 2, before they ionize neutralparticles. For this reason plasma is generated with a uniform density inthe weak magnetic field region. In addition, since the multi-pole cupsedmagnetic field is formed by arranging a plurality of permanent magnetsacting as the second static magnetic field generating means on theperiphery of the plasma generating space chamber portion 2 and byarranging the permanent magnets so that adjacent ones have polaritiesopposite to each other, not only diffused high energy electrons but alsoplasma generated by the high energy electrons can be confined in theplasma generating space chamber portion 2 with a high efficiency andtherefore it is possible to generate surely a high density plasma.Plasma generated in such a weak magnetic field region is hardlyinfluenced by the magnetic field and has good properties thatdistribution of different kinds of ions is uniform and that iontemperature is low.

On the other hand, since confinement of high energy electrons and plasmain the plasma generating space chamber portion 2 is effected with ahigher efficiency with increasing magnetic field strength in theneighborhood of the permanent magnets, in some cases magnetic fieldstrength is set at a value higher than the electron cyclotron resonancemagnetic field strength in the proximity of the permanent magnets 4.However, as described above, in the present embodiment, since thedischarge chamber 100 consists of the electron heating space chamberportion 1 formed on the downstream side from the dielectric body 6 inthe waveguide portion 5 and the plasma generating space chamber portion2 formed on the further downstream side, a strong magnetic field isformed on the upstream side of the electron heating space chamberportion 1 by the permanent magnets 3 arranged on the outer periphery ofthe electron heating space chamber portion 1, and a cusped magneticfield is formed by making the magnetic field steeply fall withdecreasing distance to the downstream side, if a microwave is suppliedby the waveguide portion 5, almost no electron heating takes place inthe electron cyclotron resonance layer formed in the proximity of thepermanent magnets 4 within the plasma generating space chamber portion2, owing to the fact that the microwave is absorbed almost completely bythe electron heating space chamber portion 1 and the cross-section ofthe plasma generating space chamber portion 2 is much larger so thatelectric field is very weak, even if the microwave leaks to the plasmagenerating space chamber portion 2.

By using the plasma thus generated, in which distribution of differentkinds of ions is uniform and ion temperature is low, it is possible tosubject the substrate 20 held on the supporting table 21 to uniformplasma processing over a wide area. Further, when a bias voltage isapplied to the substrate 20 by means of a high frequency bias powersupply 23 and a matching box 22, since the substrate 20 is irradiatedwith directive ions, it is possible to effect plasma processing such asa plasma etching having a good anisotropy, and a CVD film formationhaving a good step coverage.

FIGS. 5 to 7 show a second embodiment of the present invention.

Compared with the first embodiment, the second embodiment differsremarkably therefrom in following two points, i.e. that the electronheating space chamber portion 1 is formed so as to surround the sidesurface over the whole periphery of the plasma generating space chamberportion 2 and that the counterplate 31 forms the upper end of the plasmagenerating space chamber portion 2, opposite to the substrate 20. Thesetwo points will mainly be explained below.

In the present embodiment, a waveguide portion 5 is coupled with theperipheral wall 8b of the plasma generating space chamber portion 2,surrounding all the 4 periphery thereof, and a ring-shaped dielectricbody 6 is arranged in the waveguide portion 5 around the plasmagenerating space chamber portion 2. An electron heating space chamberportion 1 is formed in the waveguide portion 5 on the downstream side inthe transmission direction of microwave, i.e. on the side closer to thecenter axis of the plasma generating space chamber portion 2 from thedielectric body 6. In this way the discharge chamber 100 is formed inone body with the plasma generating space chamber portion 2.

In order to introduce microwaves into the electron heating space chamberportion 1 so as to be uniform along all the periphery thereof, a cavity15 is disposed on the upstream side of the waveguide portion 5 andcoupled electrically with the waveguide portion 5 through a slit 16. Inthis way microwaves introduced from a rectangular waveguide 17 coupledwith a part of the cavity 15 form stationary wave of a predeterminedmode within the cavity 15 and are introduced into the waveguide portion5 with a predetermined transmission mode through the slit 16. Byoptimizing the shape of the cavity 15 and the slit 16 it is possible tomake microwave electric field uniform and to specify the microwavetransmission mode within the waveguide portion 5.

Permanent magnets 3 acting as the first magnetic field generating meansare arranged so that every two of them put the electron heating spacechamber portion 1 therebetween in a pair. Each of the permanent magnets3 has a ring-shape surrounding the plasma generating space chamberportion 2 and is magnetized in a same polarity in directions facing thecenter axis of the plasma generating space chamber portion 2. Material,of which the permanent magnets are made, is the same as used in thefirst embodiment. The longitudinal shape of the permanent magnets 3, thewaveguide portion 5, the dielectric body 6 and the neighborhood of theelectron heating space chamber portion 1 including a part of the plasmagenerating space chamber portion 2 is the same as that shown in FIG. 4Afor the first embodiment and magnetic field formed by the permanentmagnets 3 is also almost identical to that shown in FIGS. 4A and 4C. Forthis reason, since generation process of high energy electrons whenmicrowave are introduced into the electron heating space chamber portion1 and diffusion process of these high energy electrons into the plasmagenerating space chamber portion 2 are also identical to those explainedin detail for the first embodiment, explanation thereof will be omittedhere. On the other hand, owing to the fact that the electron heatingspace chamber is formed all around the side surface of the plasmagenerating space chamber portion 2, as described above, compared to thefirst embodiment, an effect is obtained that it is possible to supplymore high energy electrons uniformly from the electron heating spacechamber portion 1 to the plasma generating space chamber portion 2.

In addition to the fact that the shape of the electron heating spacechamber portion 1 differs from that used in the first embodiment, asdescribed above, it differs further therefrom in that a counterplate 31made of a non-magnetic and electrically conductive material such asstainless steel, aluminium, etc. is mounted through an insulating spaceron the side wall 8b, in lieu of the circular upper wall 8a forming theupper end of the plasma generating space chamber portion 2 in the firstembodiment, at the same position, i.e. opposite to the substrate 20, toform the upper end of the plasma generating space chamber portion 2. Thesize of the plasma generating space chamber portion 2 is identical tothat used for the first embodiment. A matching box 32 and a highfrequency bias power supply 33 forming the bias voltage applying meansare connected to the counterplate 31. A target 30 is mounted on the sideof the counterplate 31 facing the plasma generating space chamberportion 2. In this way the present embodiment constitutes a plasmaprocessing apparatus suitable particularly for sputtering filmformation. Further another matching box 22 and another high frequencybias power supply 23 are connected to the supporting table 21 so as tobe able to apply an AC bias voltage to the substrate 20. A samefrequency, in the present embodiment a commercial frequency of 13.56MHz, is used for the two high frequency bias power supplies 33 and 23and the apparatus is so constructed that it is possible to control phasedifference between two AC bias voltages produced by the high frequencybias power supplies 33 and 23 by means of a phase control device 40.

A plurality of permanent magnets 4 acting as the second static magneticfield generating means are arranged on the outer periphery of the plasmagenerating space chamber portion 2. This plurality of permanent magnets4 are made of the same material as the permanent magnets 3 acting as thefirst static magnetic field generating means and constitute a secondpermanent magnet group 4b disposed on the side wall 8b of the plasmagenerating space chamber portion 2 with a predetermined interval andalong the side wall 8b and a third permanent magnet group 4c disposed onthe back side of the substrate 20 within the discharge chamber 100, asindicated in FIGS. 5 and 6. Adjacent ones of the permanent magnets 4have polarities opposite to each other. In this way a multi-pole cuspedmagnetic field is formed within the plasma generating space chamberportion 2 and at the same time a weak magnetic field region is formed ina wide region in the plasma generating space chamber portion 2. In thefigure reference numeral 9 indicates magnetic lines of forcerepresenting the multi-pole cusped magnetic field formed by theplurality of permanent magnets. Speaking for reference, in the presentembodiment, the magnetic field strength is 400 to 2400 G on the sidewall 8b, about 15 G at the central portion of the plasma generatingspace chamber portion 2, and lower than 10 G at the position of thesubstrate 20 and the target 30. Surrounded by this multi-pole cuspedmagnetic field, a weak magnetic field region weaker than 30 G is formedas a single space in the plasma generating space chamber portion 2 andoccupies more than a half of the plasma generating space chamber portion2 in volume.

An operation of the plasma processing apparatus in the presentembodiment will now be explained, taking a case where an SiO₂ film isformed on the substrate 20 by sputtering film formation as an example.In this case the target 30 is made of SiO₂. Mixed gas of argon assputter gas and oxygen supplementing insufficiency in oxygen in the filmformed on the surface of the substrate 20 is introduced into thedischarge chamber 100 through gas introducing means 7 so as to obtain alow gas pressure atmosphere, in which the gas pressure in the dischargechamber is in the first half of the order of 10⁻⁴ Torr. When theelectron heating space chamber portion 1 is fed with microwaves having afrequency of 2.45 GHz in this state, high energy electrons are producedin the electron heating space chamber portion 1 by the operationexplained in detail in the first embodiment and supplied to the plasmagenerating space chamber portion 2. Then these high energy electronsproduce a high density plasma over a wide region in the plasmagenerating space chamber portion 2 by the operation, which is explainedsimilarly in detail in the first embodiment.

When an AC bias voltage is applied to the counterplate 31 by means ofthe matching box 32 and the high frequency bias power supply 33 in thisstate, where a uniform high density plasma is generated over a wideregion, as described above, the surface of the target 30 is biasednegatively with respect to plasma potential. Therefore, ions in theplasma are accelerated in a sheath formed on the surface of the targetto sputter the whole surface of the target and sputtered particlesproduced in this way fly to the substrate 20 held on the supportingtable 21 at a position opposite to the target to form an SiO₂ film onthe surface of the substrate 20.

At this time, since the whole surface of the target 30 is sputtered byions in the uniform plasma in a wide region, utilization efficiency ofthe target 30 is high, which can reduce frequency of exchange of thetarget. Further, since the gas pressure in the discharge chamber is alow gas pressure, which is in the first half of the order of 10⁻⁴ Torr,sputtered particles collide only rarely with neutral particles on theway to change their trajectories, that is, sputtered particles fly wellstraight. Therefore it is possible to subject the matter to be processedto sputtering film formation having a good step coverage.

By applying further an AC bias voltage to the substrate 20 on thesupporting table 21 by means of the matching box 22 and the highfrequency bias power supply 23 during the sputtering film formation, aso-called bias sputtering film formation can be effected. By the biassputtering film formation, while forming a sputter film on thesubstrate, this film is exposed at the same time to etch-back by ioncollision. This is a film forming method, by which it is possible toform a film having a better step coverage. At this bias sputter, bycontrolling positively phase difference between the AC bias voltagesapplied to the target 30 and the substrate 20 by the high frequency biaspower supplies 33 and 23, respectively, it is possible to controlabsolute values and mutual ratio of film formation rate and etch-backrate and therefore an effect can be obtained that the film formationprocess can be easily optimized.

FIGS. 8, 9A and 9B show a third embodiment of the present invention.

The plasma processing apparatus in the present embodiment differsremarkably from that described in the second embodiment in that thewaveguide portion 5 is bent on the downstream side from the dielectricbody 6 in the waveguide portion 5 and consequently the electron heatingspace chamber portion 1 has a bent shape so that the microwaveleading-out portion 6a of the dielectric body 6 cannot be seen directlyfrom the plasma generating space chamber portion 2. Accompanied thereby,the permanent magnets 3 acting as the first static magnetic field meansarranged closely to the outer side of the waveguide portion 5 has ashape extending along the center line of the waveguide portion 5 fromthe dielectric body 6 to the downstream end thereof, as shown in thefigure so as to form magnetic field along the transmission direction ofmicrowave, as shown in FIGS. 9A and 9B. At this time, in the electronheating space chamber portion 1, the magnetic field has a strengthexceeding the electron cyclotron resonance magnetic field strength (875G) at the microwave leading-out portion 6a. The apparatus is soconstructed that the magnetic field strength is gradually attenuatedtherefrom towards the downstream side to the neighborhood of theelectron cyclotron resonance layer 12, that from the neighborhood of theelectron cyclotron resonance layer 12 it is steeply attenuated towardsthe further downstream side and it becomes 0 at the position 14 in theneighborhood of the boundary between the ending side of the electronheating space chamber portion 1 and the plasma generating space chamberportion 2, and that a cusped magnetic field is formed, in which thedirection of the magnetic field is reversed on the further downstreamside to the plasma generating space chamber portion 2.

The distance from the electron cyclotron resonance layer 12 to theposition 14 where the magnetic field strength is 0 in the neighborhoodof the boundary between the ending side of the electron heating spacechamber portion 1 and the plasma generating space chamber portion 2 inthe present embodiment is about 2 cm. Since this is smaller than themicrowave wavelength (about 12 cm in the present embodiment), it ispossible to eliminate instability factors concerning propagation andabsorption of microwave as far as possible and to utilize high electricfield microwave surely and stably for electron heating.

The construction of the apparatus is identical to that described in thesecond embodiment apart from the construction of the electron heatingspace chamber portion 1 and that means for applying the bias voltage tothe counterplate 31 is a DC bias power supply 35 and the plasmaprocessing apparatus in the present embodiment is suitable particularlyfor sputtering film formation for conductive thin films, as explainedbelow.

That is, when sputtering film formation is effected by using the plasmaprocessing apparatus in the present embodiment, since it is soconstructed that the microwave leading-out portion 6a of the dielectricbody 6 cannot be seen directly from the plasma generating space chamberportion 2, sputtered particles flying from the target 30 don't stick tothe microwave leading-out portion 6a. Consequently, even if thematerial, of which the target 30 is made, is conductive such as e.g.aluminium, etc., no conductive film is formed on the surface of themicrowave leading-out portion 6a and therefore it is possible to effectstably plasma processing of the substrate 20 in a long duration whileintroducing microwaves into the discharge chamber 100.

FIGS. 10A, 10B and 11 show a fourth embodiment of the present invention.

In the plasma processing apparatus in the present embodiment, thepermanent magnets 4a acting as the second static magnetic fieldgenerating means are mounted on the counterplate 31 by means of jigs 38on the side opposite to the side of the counterplate 31 facing theplasma generating space chamber portion 2, as indicated in FIG. 11, sothat the permanent magnets 4a are movable with respect to thecounterplate 31. Since the other construction of the apparatus isidentical to that described in the second embodiment apart from the factthat there is no target 30, explanation thereof will be omitted.

Hereinbelow an operation of the present embodiment will be explained,taking a case where an SiO₂ film is formed on the substrate 20 by biasplasma CVD film formation as an example.

At first, the permanent magnets 4a are brought close to the counterplate31 and mixed gas of monosilane acting as film forming gas, oxygen forsupplementing insufficiency in oxygen in the film formed on the surfaceof the substrate 20, and argon for etching-back the film formed on thesurface of the substrate 20 is introduced into the discharge chamber 100by means of the gas introducing means 7 so as to realize a low gaspressure atmosphere, in which the gas pressure in the discharge chamberis 10⁻⁴ ˜10⁻³ Torr. In this state, when the electron heating spacechamber portion 1 is fed with microwave having a frequency of 2.45 GHz,high energy electrons are produced in the electron heating space chamberportion 1 by the action explained in detail in the first embodiment,which gives rise to a uniform high density plasma in a wide regionwithin the plasma generating space chamber portion 2. At this time,accompanied thereby, radicals are also produced.

Ions and radicals in the high density plasma produced uniformly in thewide region as described above reach the surface of the substrate 20held on the supporting table 21 to form the SiO₂ film. At the same time,since the SiO₂ film, which is being formed on the surface of thesubstrate 20, is etched-back to be flattened by applying the AC biasvoltage to the substrate on the supporting table by means of thematching box 22 and the high frequency power supply 23, an SiO₂ filmhaving a good coverage is formed finally on the surface of the substrate20. During this film formation processing, since the permanent magnets4a form a multi-pole cusped magnetic field on the surface of thecounterplate 31 at the upper end of the plasma generating space chamberportion 2 to confine the plasma, a major part of ions in the plasma pourin the substrate 20 side supported at a position opposite to thecounterplate 31 and therefore it is possible to increase utilizationefficiency of ions.

On the other hand, when the film formation processing is effectedcontinuously, it is inevitable that films are formed on the inner wallof the discharge chamber 100. When an amount of films exceeding acertain limit is formed, films are peeled off from the wall surface,forming particles, which gives rise to contamination of the surface ofthe substrate 20. Since particularly particles produced at a part of thewall surface, which is vertically above the substrate 20, to which thecounterplate 31 corresponds in the present embodiment, fall to thesubstrate 20 by gravitation, influences thereof are important. For thisreason it is necessary to effect periodically processing for eliminatingfilms stuck to the wall surface of the discharge chamber (called plasmacleaning processing). Plasma leaning processing in the plasma processingapparatus in the present embodiment will be explained below.

At first, as indicated in FIG. 10B, the permanent magnets 4a are pulledapart from the counterplate 31 to realize a state where there is almostno magnetic field on the surface of the counterplate. Then etching gassuch as carbon tetrafluoride, etc. is introduced into the dischargechamber 100 by the gas introducing means 7 and further microwaves areintroduced from the waveguide portion 5 to generate plasma. In thisstate, when an AC bias voltage is applied to the counterplate 31 bymeans of the matching box 32 and the high frequency bias power supply33, the surface of the counterplate 31 is biased negatively with respectto the plasma potential. Therefore ions in the plasma are accelerated ina sheath formed on the surface of the counterplate 31 to collide withthe counterplate 31. In this way it is possible to eliminate films stuckto the surface of the counterplate 31 with a high speed. At this time,since the state where there is almost no magnetic field on the surfaceof the counterplate 32 is realized, as described above, the wholesurface of the counterplate is uniformly cleaned.

As described above, in the present embodiment, since it is possible toparticularly clean well the counterplate 31 having remarkable influenceson particle contamination of the substrate 20 on the part of the wallsurface, which is vertically above the substrate 20, a significanteffect of cleaning processing can be obtained. Similarly cleaning of thesupporting table 21 can be effected by applying the AC bias voltage tothe supporting table 21 by means of the matching box 22 and the highfrequency bias power supply 23. Further, if phase difference between thetwo AC bias voltages applied to the counterplate 31 and the supportingtable 21 by the high frequency bias power supplies 33 and 23,respectively is controlled positively, it is possible to optimize plasmacleaning for the whole apparatus.

We claim:
 1. A plasma processing apparatus comprising:at least onewaveguide portion for introducing microwaves; a plasma generating spacechamber portion coupled with said waveguide portion; first staticmagnetic field generating means consisting of permanent magnetssurrounding said waveguide portion, which have an electron cyclotronresonance magnetic field strength at least at a part of said waveguideportion and said plasma generating space chamber portion and forming acusped magnetic field, a direction of which is reversed along atransmission direction of microwaves in said waveguide portion; secondstatic magnetic field generating means consisting of permanent magnetsarranged around said plasma generating space chamber portion, everyadjacent two of which have polarities opposite to each other; means forholding matter to be processed facing said plasma generating spacechamber portion; a counterplate facing said plasma generating spacechamber portion, opposite to said matter to be processed; and means forapplying a bias voltage to said counterplate.
 2. A plasma processingapparatus comprising:at least one waveguide portion for introducingmicrowaves; a plasma generating space chamber portion coupled with saidwaveguide portion; first static magnetic field generating meansconsisting of permanent magnets surrounding said waveguide portion,which have an electron cyclotron resonance magnetic field strength atleast at a part of said waveguide portion and said plasma generatingspace chamber portion and forming a cussed magnetic field, a directionof which is reversed along a transmission direction of microwaves insaid waveguide portion; second static magnetic field generating meansconsisting of permanent magnets arranged around said plasma generatingspace chamber portion, every adjacent two of which have polaritiesopposite to each other; means for holding matter to be processed facingsaid plasma generating space chamber portion; means for applying an ACbias voltage to said matter to be processed; a counterplate facing saidplasma generating space chamber portion, opposite to said matter to beprocessed; means for applying an AC bias voltage to said counterplate;and means for controlling a phase of said AC bias voltage applied tosaid matter to be processed and a phase of said AC bias voltage appliedto said counterplate.
 3. A plasma processing apparatus comprising:atleast one waveguide portion for introducing microwaves; an electronheating space chamber portion formed on a downstream side with respectto a dielectric body disposed within said waveguide portion; a plasmagenerating space chamber portion coupled with said electron heatingspace chamber portion; first static magnetic field generating meansconsisting of permanent magnets surrounding said electron heating spacechamber portion, which produce a strong magnetic field exceeding anelectron cyclotron resonance magnetic field strength at a microwaveleading-out portion of said electron heating space chamber portion andwhich form a cusped magnetic field, a direction of which is reversedalong a transmission direction of microwaves in said waveguide portion;second static magnetic field generating means consisting of permanentmagnets arranged around said plasma generating space chamber portion,every adjacent two of which have polarities opposite to each other;means for holding matter to be processed facing said plasma generatingspace chamber portion; a counterplate facing said plasma generatingspace chamber portion, opposite to said matter to be processed; andmeans for applying a bias voltage to said counterplate.
 4. A plasmaprocessing apparatus comprising:at least one waveguide portion forintroducing microwaves; an electron heating space chamber portion formedon a downstream side with respect to a dielectric body disposed withinsaid waveguide portion; a plasma generating space chamber portioncoupled with said electron heating space chamber portion; first staticmagnetic field generating means consisting of permanent magnetssurrounding said electron heating space chamber portion, which produce astrong magnetic field exceeding an electron cyclotron resonance magneticfield strength at a microwave leading-out portion of said electronheating space chamber portion and which form a cusped magnetic field, adirection of which is reversed along a transmission direction ofmicrowaves in said waveguide portion; second static magnetic fieldgenerating means consisting of permanent magnets arranged around saidplasma generating space chamber portion, every adjacent two of whichhave polarities opposite to each other; means for holding matter to beprocessed facing said plasma generating space chamber portion; means forapplying an AC bias voltage to said matter to be processed; acounterplate facing said plasma generating space chamber portion,opposite to said matter to be processed; means for applying an AC biasvoltage to said counterplate; and means for controlling a phase of saidAC bias voltage applied to said matter to be processed and a phase ofsaid AC bias voltage applied to said counterplate.
 5. A plasmaprocessing apparatus according to claim 1, wherein a target is held on aside of said counterplate facing said plasma generating space chamberportion.
 6. A plasma processing apparatus according to claim 1, whereinsaid permanent magnets acting as said second static magnetic fieldgenerating means are arranged on a side opposite to a side of saidcounterplate facing said plasma generating space chamber portion andsaid permanent magnets are movable with respect to said counterplate. 7.A plasma processing apparatus according to claim 1, wherein saidwaveguide portion is bent.
 8. A plasma processing apparatus according toclaim 1, wherein said waveguide portion is formed on a side surface ofsaid plasma generating space chamber portion.
 9. A plasma processingapparatus according to claim 8, wherein said waveguide portion isformed, surrounding the whole side surface of said plasma generatingspace chamber portion.
 10. A plasma processing method, whereby a matterto be processed is held in a plasma processing apparatus according toclaim 1 and plasma generated in a plasma generating space chamberportion is made to react with said matter to be processed.
 11. A plasmaprocessing apparatus comprising:at least one waveguide portion forintroducing microwaves; a plasma generating space chamber portioncoupled with said waveguide portion; a first plurality of permanentmagnets surrounding said waveguide portion, which have an electroncyclotron resonance magnetic field strength at least at a part of saidwaveguide portion and said plasma generating space chamber portion andforming a cusped magnetic field, a direction of which is reversed alonga transmission direction of microwaves in said waveguide portion; asecond plurality of permanent magnets arranged around said plasmagenerating space chamber portion, adjacent ones of which have polaritiesopposite to each other; a support onto which matter to be processed isplaced so as to be facing said plasma generating space chamber portion;a counterplate facing said plasma generating space chamber portion,opposite to said matter to be processed; and means for applying a biasvoltage to said counterplate.
 12. A plasma processing apparatuscomprising:at least one waveguide portion for introducing microwaves; aplasma generating space chamber portion coupled with said waveguideportion; a first plurality of permanent magnets surrounding saidwaveguide portion, which have an electron cyclotron resonance magneticfield strength at least at a part of said waveguide portion and saidplasma generating space chamber portion and forming a cusped magneticfield, a direction of which is reversed along a transmission directionof microwaves in said waveguide portion; a second plurality of permanentmagnets arranged around said plasma generating space chamber portion,adjacent ones of which have polarities opposite to each other; a supportonto which matter to be processed is placed so as to be facing saidplasma generating space chamber portion; means for applying an AC biasvoltage to said matter to be processed; a counterplate facing saidplasma generating space chamber portion, opposite to said matter to beprocessed; means for applying an AC bias voltage to said counterplate;and means for controlling a phase of said AC bias voltage applied tosaid matter to be processed and a phase of said AC bias voltage appliedto said counterplate.
 13. A plasma processing apparatus comprising:atleast one waveguide portion for introducing microwaves; an electronheating space chamber portion formed on a downstream side with respectto a dielectric body disposed within said waveguide portion; a plasmagenerating space chamber portion coupled with said electron heatingspace chamber portion; a first plurality of permanent magnetssurrounding said electron heating space chamber portion, which produce astrong magnetic field exceeding an electron cyclotron resonance magneticfield strength at a microwave leading-out portion of said electronheating space chamber portion and which form a cusped magnetic field, adirection of which is reversed along a transmission direction ofmicrowaves in said waveguide portion; a second plurality of permanentmagnets arranged around said plasma generating space chamber portion,adjacent ones of which have polarities opposite to each other; a supportonto which matter to be processed is placed so as to be facing saidplasma generating space chamber portion; a counterplate facing saidplasma generating space chamber portion, opposite to said matter to beprocessed; and means for applying a bias voltage to said counterplate.14. A plasma processing apparatus comprising:at least one waveguideportion for introducing microwaves; an electron heating space chamberportion formed on a downstream side with respect to a dielectric bodydisposed within said waveguide portion; a plasma generating spacechamber portion coupled with said electron heating space chamberportion; a first plurality of permanent magnets surrounding saidelectron heating space chamber portion, which produce a strong magneticfield exceeding an electron cyclotron resonance magnetic field strengthat a microwave leading-out portion of said electron heating spacechamber portion and which form a cusped magnetic field, a direction ofwhich is reversed along a transmission direction of microwaves in saidwaveguide portion; a second plurality of permanent magnets arrangedaround said plasma generating space chamber portion, adjacent ones ofwhich have polarities opposite to each other; means for holding matterto be processed facing said plasma generating space chamber portion;means for applying an AC bias voltage to said matter to be processed; acounterplate facing said plasma generating space chamber portion,opposite to said matter to be processed; means for applying an AC biasvoltage to said counterplate; and means for controlling a phase of saidAC bias voltage applied to said matter to be processed and a phase ofsaid AC bias voltage applied to said counterplate.
 15. A plasmaprocessing apparatus according to claim 11, wherein a target is held ona side of said counterplate facing said plasma generating space chamberportion.
 16. A plasma processing apparatus according to claim 11,wherein said second plurality of permanent magnets are arranged on aside opposite to a side of said counterplate facing said plasmagenerating space chamber portion and said permanent magnets are movablewith respect to said counterplate.
 17. A plasma processing apparatusaccording to claim 11, wherein said waveguide portion is bent.
 18. Aplasma processing apparatus according to claim 11, wherein saidwaveguide portion is formed on a side surface of said plasma generatingspace chamber portion.
 19. A plasma processing apparatus according toclaim 18, wherein said waveguide portion is formed, surrounding thewhole side surface of said plasma generating space chamber portion. 20.A plasma processing method, whereby matter to be processed is held in aplasma processing apparatus according to claim 11 and plasma generatedin a plasma generating space chamber portion is made to react with saidmatter to be processed.
 21. A plasma processing apparatus comprising:atleast one waveguide portion for introducing microwaves; a plasmagenerating space chamber portion coupled with said waveguide portion;first static magnetic field generating means having permanent magnetssurrounding said waveguide portion, and having an electron cyclotronresonance magnetic field strength at least at a part of said waveguideportion and said plasma generating space chamber portion and forming acusped magnetic field, a direction of which is reversed along atransmission direction of microwaves in said waveguide portion; secondstatic magnetic field generating means having permanent magnets arrangedaround said plasma generating space chamber portion, adjacent ones ofwhich have polarities opposite to each other; means for holding matterto be processed facing said plasma generating space chamber portion; acounterplate facing said plasma generating space chamber portion,opposite to said matter to be processed; and means for applying a biasvoltage to said counterplate.
 22. A plasma processing apparatuscomprising:at least one waveguide portion for introducing microwaves; aplasma generating space chamber portion coupled with said waveguideportion; first static magnetic field generating means having permanentmagnets surrounding said waveguide portion, and having an electroncyclotron resonance magnetic field strength at least at a part of saidwaveguide portion and said plasma generating space chamber portion andforming a cusped magnetic field, a direction of which is reversed alonga transmission direction of microwaves in said waveguide portion; secondstatic magnetic field generating means having permanent magnets arrangedaround said plasma generating space chamber portion, adjacent ones ofwhich have polarities opposite to each other; means for holding matterto be processed facing said plasma generating space chamber portion;means for applying an AC bias voltage to said matter to be processed; acounterplate facing said plasma generating space chamber portion,opposite to said matter to be processed; means for applying an AC biasvoltage to said counterplate; and means for controlling a phase of saidAC bias voltage applied to said matter to be processed and a phase ofsaid AC bias voltage applied to said counterplate.
 23. A plasmaprocessing apparatus comprising:at least one waveguide portion forintroducing microwaves; an electron heating space chamber portion formedon a downstream side with respect to a dielectric body disposed withinsaid waveguide portion; a plasma generating space chamber portioncoupled with said electron heating space chamber portion; first staticmagnetic field generating means having permanent magnets surroundingsaid electron heating space chamber portion, for producing a strongmagnetic field exceeding an electron cyclotron resonance magnetic fieldstrength at a microwave leading-out portion of said electron heatingspace chamber portion and which form a cusped magnetic field, adirection of which is reversed along a transmission direction ofmicrowaves in said waveguide portion; second static magnetic fieldgenerating means having permanent magnets arranged around said plasmagenerating space chamber portion, adjacent ones of which have polaritiesopposite to each other; means for holding matter to be processed facingsaid plasma generating space chamber portion; a counterplate facing saidplasma generating space chamber portion, opposite to said matter to beprocessed; and means for applying a bias voltage to said counterplate.24. A plasma processing apparatus comprising:at least one waveguideportion for introducing microwaves; an electron heating space chamberportion formed on a downstream side with respect to a dielectric bodydisposed within said waveguide portion; a plasma generating spacechamber portion coupled with said electron heating space chamberportion; first static magnetic field generating means having permanentmagnets surrounding said electron heating space chamber portion, forproducing a strong magnetic field exceeding an electron cyclotronresonance magnetic field strength at a microwave leading-out portion ofsaid electron heating space chamber portion and which form a cuspedmagnetic field, a direction of which is reversed along a transmissiondirection of microwaves in said waveguide portion; second staticmagnetic field generating means having permanent magnets arranged aroundsaid plasma generating space chamber portion, adjacent ones of whichhave polarities opposite to each other; means for holding matter to beprocessed facing said plasma generating space chamber portion; means forapplying an AC bias voltage to said matter to be processed; acounterplate facing said plasma generating space chamber portion,opposite to said matter to be processed; means for applying an AC biasvoltage to said counterplate; and means for controlling a phase of saidAC bias voltage applied to said matter to be processed and a phase ofsaid AC bias voltage applied to said counterplate.
 25. A plasmaprocessing apparatus according to claim 21, wherein a target is held ona side of said counterplate facing said plasma generating space chamberportion.
 26. A plasma processing apparatus according to claim 21,wherein said permanent magnets acting as said second static magneticfield generating means are arranged on a side opposite to a side of saidcounterplate facing said plasma generating space chamber portion andsaid permanent magnets are movable with respect to said counterplate.27. A plasma processing apparatus according to claim 21, wherein saidwaveguide portion is bent.
 28. A plasma processing apparatus accordingto claim 21, wherein said waveguide portion is formed on a side surfaceof said plasma generating space chamber portion.
 29. A plasma processingapparatus according to claim 28, wherein said waveguide portion isformed, surrounding the whole side surface of said plasma generatingspace chamber portion.
 30. A plasma processing method, whereby matter tobe processed is held in a plasma processing apparatus according to claim21 and plasma generated in a plasma generating space chamber portion ismade to react with said matter to be processed.